Heretofore, an intake passage structure for a motorcycle has been known in which a connecting tube for air to pass through to a throttle body after being purified by an air cleaner is formed of three separate components outside the air cleaner (see Japanese Patent Application Publication No. 2008-248718, for example). Specifically, of the three components, the upstream and downstream tubes are made of rubber, and the middle tube connecting them to each other and having multiple bent portions is formed by blow molding. In this configuration, the connecting tube is provided in such a way as to bend at multiple spots within a small space. In this way, the length of the connecting tube can be increased, thereby making it possible to increase the low-speed torque of the engine.